Coastal Plains Ecoregion - National Lakes Assessment Results
Key Results
An estimated 51,700 lakes in the Coastal Plains ecoregion are represented in the National Lakes Assessment (NLA). Of these lakes, 18% are natural and 82% are man-made.
The NLA uses trophic state as an important indicator of lake condition and assesses the extent of biological condition and key stressors in the nation’s lakes.
- In the Coastal Plains, 34% of lakes are rated as hypereutrophic while 44% are eutrophic, 11% are mesotrophic and 11% are oligotrophic.
- The most widespread stressors assessed are phosphorus, lake habitat complexity, and lakeshore disturbance each with 38% of lakes in poor condition.
- Cyanobacteria are one-celled photosynthetic organisms that normally occur at low levels. Under eutrophic conditions, cyanobacteria can multiply. Not all cyanobacterial blooms are toxic, but some may release toxins, such as microcystins. For information about risks at specific locations, recreational water users should check with state, tribal or local governments.
- Based on microcystins, 6% of lakes in the Coastal Plains are above the recreational benchmark.
Change from 2012*
- For the Coastal Plains, the NLA reports that the percent of lakes in good condition for zooplankton increased by 28 percentage points between 2012 and 2017 and the percent of lakes in poor condition decreased by 34 percentage points.
- The percent of lakes with atrazine detections decreased by 11 percentage points and the percent of lakes with large drawdown decreased by 7 percentage points.
To access more ecoregional specific information, please visit the interactive NLA Dashboard.
* The change analysis is based on information from two points in time – 2012 and 2017.